Thanks for the feed back - especially from CD/Brian - having it from a cruiser helps.
The Gemini's 80w, 3 optima's and 12C controller with an XBM was okay for that boat because of the propane refridge freezer - this boat and it's intended use are so much different I'm really feeling out of my league.

Brian, going cruising about October 2015, ICW to Fla, then island hopping around counter clockwise most likely - KW to Cancun style, then onward around the rim. Nothing set in stone, but heavily toed into the sand.

MS, I hear you on the heat. Idea scrapped firmly. Let's say I go with 6v's as described and 4 of them fit in the compartment I've already detailed. Is it safe to put the other 4 within 8 feet of 0/0 cable and make it one bank - without excessive voltage drop killing me?

Hello, that bank isn't 'in' the bilge - it's well above it, high and dry.

I may alter my davits to hold two panels - I'm looking at the specs and it says a 240w is 65 x 40 (average, roughly). That's a big chunk of sky.
Current davits:

Really weren't made for that much panel - and they are too low to duck under when using the ladder.

2015 - no telling where we will be! Hopefully see you out there though.

C,

I would consider (maybe) removing the davits and have an arch built that hung off the back. You have a wonderful design for it. I would make it 2 " out of aluminum. It will be very light, relatively inexpensive, and large enough to run large diameter wire(s) - think gps, wifi, cell booster, solar panels, stern lighting, etc. That is what we have running through our solar arch right now. The light hitting the stern is a Godsend when anchored and coming in at night... esp given you dont have a sugar scoop. I am not a fan of SS for arches. Way too much weight and small diameter tubing. If you build a ss arch to accomdate that much wiring, it will sink the boat and cost a small fortune.

If you design the arch right, you will be able to double it as a davit. Aluminum being light, you may get away with getting it higher off the water line with less weight aloft. That was my one screw up... the arch will hold my tender but I already had davits and designed it with that in mind. Of course, you could do the same, but going back, I would make them one unit. I am not a big fan of when people make these massive davit towers that haul the dink 12+ feet out of the water, but you will want to keep engine and all out of the water and much of your coastal will be with her sitting there versus on deck. Keep the barnacle growth down and the speed up. Remember, the shaft of your tender hangs down a couple of feet under your tender... so when designing, keep that in mind (should you care to do that at all). ALso, you might be able to sell your current davits online to someone not cruising. ALl of this is just my opinion and obviously feel free to toss it away. It was just my first thought.

I LOVE that aft deck you have. Keep it clear. Nothing better than a couple of chairs there on a nice sunset.

I like the Irwins. Congrats on your boat. We ran across a great couple in the Tortugas that sailed a Irwin and had returned from a very long time in the Bahamas. She will make a good home for you.

ALl the best. Feel free to call or PM me with any questions if you want. PM me for phone number. Never a prob for you.

An amazing amount of information. I will have to read this several times to even ask an intelligent question. Would you, could you add two more of the same size battery's in the salon sole to a remote location? Say under the V berth or in the stern lazaret (trunk). Given a white hull and low to the waterline. An arch is also on my mind along with a Bimini located array even though shade impedes the creation. Don't some types of panels stand shade better? This is all very,very interesting.

Tim,
Panels with multiple Diodes will help with partial shade - they help by shutting off the portion of the panel that is in shade (as determined by a lower voltage output) from the rest of the panel's output.
Kyocera's have this in the 240w panel. It's Max output is on the order of +30v, therefore one COULD say they tolerate shade.

The davits are aluminum - we are indeed looking at raising them or modifying them for panels.

"Panels with multiple Diodes will help with partial shade - "AFAIK they are trying not to confuse the customers by talking tech, but those panels are actually multiple arrays (i.e. 2-3-4 arrays) joined to a common output through isolation diodes. So if a shadow falls on any one array, that array loses voltage but the others are isolated from it. I'm not sure how much practical value that has though. Consider, if a panel has three "12" volt arrays arranged ||| next to each other. A vertical shadow on one array, will leave two at full voltage. But a horizontal shadow will knock out all three.
So unless the shadow is aligned so as to JUST fall on one array in the panel...with or without isolation diodes, that shadow would still knock down the output from the entire panel, wouldn't it?

As I said above - we are looking at extending / modifying the existing davits - adding an arch essentially - but more.
The current davits will have an arm added to 'extend' the dingy out further from the boat prior to raising/dropping.

We'll need that because I'm adding a 'swim' platform across the stern - 18 inches deep, 8 feet wide. I seriously don't like the idea of leaping from the dinghy to a narrow ladder..

The arch will go up far enough so we can easily com up the ladder and board the boat without UN-necessary wear and tear on my bald head. I'm too old to crawl under a solar panel to get onto the boat.

That arch will also be a good fastening point for the umbrella and screen enclosure that will stretch from bimini to arch - so we can actually use that back deck as a patio.

3 years, a lot of elbow grease - and a couple boat bucks. Wish me luck.

Chuckles-
To me, an engineer is someone who can make extremely clever & elegant use of gears, levers, cams and motions. You might try to look at some scheme that would rotate the davit arms instead of extending them out. i.e. the arms rotate inboard and come closer to the transom, rotate outboard and separate and move the dink further astern. Or, the davit arms lift (cable pull) to come in close to the stern, and as they lower, they arc outwards and further away from it. Somewhere in there will be a solution that needs the least weight and still has good strength, as opposed to just extending them.

I saw a Mercedes with a single windshield wiper, in the middle of the windshield base. Somehow that damned thing is cammed up so it moves in a figure 8 and sweeps both sides of the glass! One blade, one motor, hocus-pocus and it does the work of two. Now that I call elegant engineering.

"Panels with multiple Diodes will help with partial shade - "AFAIK they are trying not to confuse the customers by talking tech, but those panels are actually multiple arrays (i.e. 2-3-4 arrays) joined to a common output through isolation diodes. So if a shadow falls on any one array, that array loses voltage but the others are isolated from it. I'm not sure how much practical value that has though. Consider, if a panel has three "12" volt arrays arranged ||| next to each other. A vertical shadow on one array, will leave two at full voltage. But a horizontal shadow will knock out all three.
So unless the shadow is aligned so as to JUST fall on one array in the panel...with or without isolation diodes, that shadow would still knock down the output from the entire panel, wouldn't it?

Quit trying to confuse the sailors

But yes, absolutely.
In the case of the K's - they are aligned along the length - same orientation as the boom.

Chuckles-
To me, an engineer is someone who can make extremely clever & elegant use of gears, levers, cams and motions. You might try to look at some scheme that would rotate the davit arms instead of extending them out. i.e.

On Voyage 44 catamarans the boom has an extension that inside the boom.
A simple 2:1 setup pulls the extension out - and springs pull it back in.
The dinghy sits on chocks on the back deck, you lift it, extend it, then drop it.

To me, that's simple, and if it breaks you can still manhandle the dinghy out.

As I said above - we are looking at extending / modifying the existing davits - adding an arch essentially - but more.
The current davits will have an arm added to 'extend' the dingy out further from the boat prior to raising/dropping.

We'll need that because I'm adding a 'swim' platform across the stern - 18 inches deep, 8 feet wide. I seriously don't like the idea of leaping from the dinghy to a narrow ladder..

The arch will go up far enough so we can easily com up the ladder and board the boat without UN-necessary wear and tear on my bald head. I'm too old to crawl under a solar panel to get onto the boat.

That arch will also be a good fastening point for the umbrella and screen enclosure that will stretch from bimini to arch - so we can actually use that back deck as a patio.

3 years, a lot of elbow grease - and a couple boat bucks. Wish me luck.

Take a look at Elan... the sailboat modified by Scott and Wendy Bannerot. They wrote the book, "Cruiser's Handbook of Fishing." They modified their stern in a way that I think you might consider. I actually talked to Kris about that tonight. I agree about crawling up that swept back, which is also why I have seen several boats modified into a "modified sugar scoop". Anyways, I am not saying you would want to do what they did... just might give you some ideas. Your boat would be suitable for such a modification I suspect.

Also, if you don't have Scott and Wendy's book... get it. It is to cruisers fishing what Calder is to electrical. Best fishing book I have ever owned.

Look forward to seeing you out here. In all seriousness, let me know if I can help any.

"Panels with multiple Diodes will help with partial shade - "AFAIK they are trying not to confuse the customers by talking tech, but those panels are actually multiple arrays (i.e. 2-3-4 arrays) joined to a common output through isolation diodes. So if a shadow falls on any one array, that array loses voltage but the others are isolated from it. I'm not sure how much practical value that has though. Consider, if a panel has three "12" volt arrays arranged ||| next to each other. A vertical shadow on one array, will leave two at full voltage. But a horizontal shadow will knock out all three.
So unless the shadow is aligned so as to JUST fall on one array in the panel...with or without isolation diodes, that shadow would still knock down the output from the entire panel, wouldn't it?

I don't know about interlacing diodes, but on my panels, there is a double option to connect to the diode or pass it. It is visible in the connection box. I would wonder why they would take the three panels on that and connect to diodes and then run through yet another diode since it would reduce the effectiveness of the panel with each diode. But I am no expert. ALl I can say is that I have helped install other panels that were not Kyocera and there really is a difference. Not saying they are the best... but they are the best I have come across.

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